Carburetor



E. OLSON CARBURETOR April 21, 1953 Filed Dec. 14, 1949 R. W V 5 mw.

4.0 18m m fl 1 .H A 5 wm MM J .J h

Patented Apr. 21, 1953 CARBURETO'R lmer Olson. Rochester, N.1 assignor to Genoral Motors Corporation, Detroit, Mick., a corporation of Delaware Application December 14, 1949, serial Nu. 182,821

16v Claims.

This inventicnA reates to carburetors for imternal combustion engines, particulaiiy for auto motive. use and is an improvemcnt: en the type of carhuretor disclosed in anplio st', hndizng Bip* plication Serial` No. iQ9,3147, .imion-.8119A 1949. The principal obiect of. the present invention is to provide a fucl passaec for oonveyns fueI from` the fuel chamher to, the fuel inlet or inicts through which fucl is discharged into the mixf iiire message of the oarbn-retor which is so oonf structeci that there will be a substantialiy even flowof fucl, through suchpassagc under all, open atine conditions and, temperatur-es and which the ioitmation of vapor bilhbics large enough to materialiyolosiruct thel flow of .fue'lis preven-teot at: ony temperature at whichl the engine may operat.

This object is attaincd. by' the nrovisioxi of a fuel conduit comprising` two parts,l one of which is a substantially Vertical passage formed in. a member extending downwardly into the fuel-` in the fuel chamber, which conneots at` its. upper end with a suhstantially ho-rizontal passage least ing to the main and idling fuel inlets, the point in the fuel conduit where. the Vertical and horizvontal passages join, the wall of the` conduit is fiareci outwardly along the horizontal axis so that the size of the conduit is progressively increased in the direction ofV fuel. flow.. wall is also fiared outwardly in. a downwai'd direction while` the surface at the top immediately aboye the upper end of the`` Vertical fuel passage is not normal to the` axis of such Vertical passaee, hut is arrangecl at an obtuse angle thereto in the d-ireotion of fuelflow` This arraneement does not prevent formation of vapor bullohles,l as small bubbles are formed atv high temperatures. HoweverA the. arrangement eliminates the for-mation of a, sharp corner where`` such small. bubbles would tend to collect and increase in size..

As'V shown. in the drawings. there is formed at the point of connection of the Vertical and horizontal passages a, small Chamber of largerv cross sectional area than either of the passages-x in fact, this chamber is as large at its bottom the upper end of the member in which the Vertical fuelpassage, is foi'iiied` and the upper end of. such member is suitably seovzred, the bottorn of said chambcn. The side walls of such Chamber are fiared; outwariiiy along the axis.J of theV hoi'izontal Dassaae in the direction of flow of the fui as shown in Fie.`` The side walls of the chambei' arefi-areci outwaroiy towamiV the bottom of said chamher aslshown in Figs., 5; anel; 6 and the upper surface of said chamber is fiaredsupwardly inithe 2` direction offiow of. the fuel as; shown i-n Fiss. 1` and 2a Eurthen applicant has provided in the horizontal. iuci passage adiaocnt the above desoribed chan'iber, a, partition plate which is secureii in position` along the axis of theV horizontal passage cii-.vcling such passage into upper and lower partsq This plate causes a fiow through the upper part of the passage at hijher. Velocity than through the lower part. Also, although the specific fiareci formation of the chamber at the J-unction of the Vertical anel1 horizontal fuel passages substantially prevents the formation of vaporbuhbles of any appreciahle size, if bubbles of such a size are ever formecl, the.- partition will break. un such biibloles emi cause siich small bubbles as are formed in the fuel concluit at high. temperatures to flow throughthe upper part of the passage at high Velocity, so. that one fuel flow isfnot retaijcled.` It has`y also been found by; actual experiment Athat the partition plate is more effective when it. is somewhat shorter than that pon tion of the horizontal fuel passage which extends from the Vertical leg of the fuel passage to the main fuel inlet.

Further objects and. advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawingjs wherein a, preferred mhodiment of. the present invention is clearly shown.

In4` the. drawings:

Fig., 1 is a Vertical section through the carbui'etor and fuel, supply passage.

lilig.` 2 is a` detail section showing; the construc tionv of the fuel conduit where the Vertical and horizontal passages connect.

Fig. a is a horizontal section on the line 3.-3 of Fig. 2,

i'ig's.k Li, 5 and- 6Y are Sections on the lines 4-4, 5.--5 emi 6-5 respectively, of Figi.` 3.

Refcrring. to Fiat.. li the oarouretor shown thereinj comprises three separate castings numhered I, 2 and 3, respectively. The casting` l is the. arburetor Outlet which is` aclaptedto be f connected with the miare manifcli m, the usoal maoner.: the casting 2 is positioned above the outlet casting i end has a Constant; level iuel ohamber' 2a formeo thercin,``` while the casting' 3 forms a cover for the fool. Chamber anel also has the air iotake 4 formeci therciii..` These three castines. are separateii by eeslsets to form tight ionis andto limit the transfer of heat. between the eastings as much: as: possible by pre'tenting ai metallio contact of the castings with each O er.

aeseci In the outlet casting l a throttle shaft A is suitably journalled and secured to such shaft is the usual throttle valve 6 which is manually adjustable by means not shown to control the volume of combustible mixture which is supplied by the carburetor to the engine.

In the casting 3 a choke valve 'I is positioned and this Valve is secured to a shaft 3 which is suitably mounted in the casting 3 for rotation. The choke valve in the carburetor disclosed herein is manually operated and, when the engine is Operating at normal temperature, is adapted to be positioned in wide open position so as not toV restrict the quantity of air entering the carburetor, but is adapted to be closed, or partly closed, by the manual Operating connections when the engine is started cold in order to facilitate starting, the position to which the choke valve is moved being dependent upon the temperature at the time of starting. The choke valve is adapted to be moved to different positions by means of the arm numbered 9 which is adapted to be operated by a connection leading to the dash which is not shown herein, but is a conventional construction. The arm 9 operates the choke valve through mechanism which needinot be described herein, but is fully shown and described in the copending application above referred to. It may be said, however, that the operation of the choke valve by the arm 9 is e'ected through a spring l which holds the choke valve yieldingly closed, so that when the engine starts to run under its own power, the increase in engine suction which then occurs can pull the valve open to some extent against the force of the spring 10, so as to prevent over-choking. i

In the carburetor shown herein, the choke valve is also designed to operate the throttle so as to move the throttle slightly toward open position when the choke valve is moved to its fully closed position in order that the idling speed may be somewhat increased when the choke valve is closed. This is done for the purpose of providing a somewhat faster than normal idling when the choke Valve is closed at low temperatures which is desirable to prevent stalling. The Operating connections between the choke valve and the throttle valve for efiecting this movement are indicated generally by the reference numeral li. Since this mechanism has nothing to do With the invention in this application, it is not illustrated in detail and will not be described, but such mechanism is fully shown and described in the aforesaid copending application.

As already indicated, air is admitted to the carburetor through the air inlet 4 and fuel is supplied to the carburetor through a main fuel nozzle 42 which terminates at the throat of a small Venturi tube l3 which, itself, terminates at the throat of a large Venturi tube U3 integral with the casting 2 and forming a part of the mixture passage which extends vertically through the carburetor. The purpose of these Venturi tubes is, of course, to increase the Velocity of air flow past the end of the main fuel nozzle IZ to create a partial vacuum adiacent the nozzle outlet in the usual and well known manner. Fuel is also supplied to the intake passage by an idling fuel inlet which is not shown herein, but which terminates in an orifice communicating with the intake passage at the point adjacent and slightly posterior to the edge of the throttle valve 6 when the latter is in closed position.

Fuel is supplied to both of these fuel inlets from the fuel chamber 2a and fuel is supplied to the latter through a coupling i which is screwed into the casting 3 and to which a fuel supply pipe extending to the main fuel tank of the Vehicle is adapted to be connected. Fuel which is supplied through the coupling |5 enters a passage 16 formed in the casting 3 and flows through a passage in a nipple l', which is screwed in the wall of the casting 3, and communicates with the fuel bowl 2a when the parts are assembled as shown in Pig. 1. The flow of fuel through the passage ll into the bowl is controlled by a valve 18 which cooperates with the passage ll and rests on one arm of a lever i9 which is pivoted on a pin 20 fixed in position in the wall of the fue1 chamber 2a. The lever 19 is connected to the fioat mechanism which is not shown, but which is received within the chamber 2aand when the fuel level in said chamber reaches a definite height, the fioat lifts the lever i9 so as to close the valve 18 and cut oif the flow of fue1 into the fioat chamber in the usual way. The float mechanism is of conventional construction and has nothing to do with the invention which is claimed in this application.

Before describing the fuel passage which conveys fuel from the fioat chamber 2a to the main and idling fue1 inlets, the construction of which constitutes the subject matter to which the claims of this application are directed, attention is called to the fact that the carburetor is provided with an accelerator pump which is operated manually upon sudden opening movements of the throttle to provide a charge of fuel in addition to the fuel supplied by the ordinary fuel inlet, in order to enrich the mixture for acceleration in the usual way. The construction of this accelerator pump constitutes no part of the present invention, but the pump includes a cylinder 25 into which fue1 flows from the fioat chamber 2a, through a passage not shown, and slidable in the cylinder is a pump piston 26 which is operated by a spring 27 that is compressed when the throttle is opened suddenly, by means of an arm 26a which is pulled downwardly when the throttle is opened. This compression of the spring effects a delayed downward movement of the piston 26 which takes place as the spring expands following its compression by the throttle, as the latter is opened and as the piston moves downwardly, in the manner described, it forces fuel from the space below the piston into the mixture passage to supply the additional fuel above referred to for acceleration purposes. This pump mechanism is fully shown and described in the copending application above referred to and will not be further described herein, since its construction is entirely immaterial so far as the present invention is concerned. A tube 28 which connects therupper end of the cylinder 25 with the carburetor intake serves as a vent for escape of any fue1 bubbles which may collect Within the cylinder 25 and as a vent for the fuel chamber 2a.

The construction which has been generally described above is the same as that disclosed in application S. N. 109,347 and the construction of the entire carburetor is the same as what is shown in such application except the fuel conduit which Supplies fuel to the main and idle fuel inlets. In this application, as in the earlier application, such fue1 conduit comprises three parts or passages which together make up a conduit shaped substantially like an inverted U, one part aoe-accx or passage being substantially Vertical and extending down-wardly into the -ioat chamber and connecting at its upper end with a. hori'zontal passage formed in casting 3, which, in turn, connects` at its other end with a substantiallyvertical passage that extend's downwardly to the idling fuel inlet, themain fuel inlet communicating with the horizonta'l portion of thepassage substantially midlway between its ends. As shown in` Fig. I, the fuel conduit includes a Vertical passage 3B formed in a member 3! which, at its upper end. isseeured in any suitable way in a. bore or chamber 31a formed in the casting 3. This member, at its lower end, has a cal-ibratedplug 32 screwed into it which meters the fuel supplied to passage 30. Communicating with the chamber`` 3m is: a,

horizontal passage 33 which, at its` left end, as shown in Fig. 1,` connects with a Vertical passage 34 which extends downwardly the wall of the casting 2 and communicates at its lower endwith a passage 351 which leads to the idlng fuel inlet.V which is not shown hcrein but is of the same construction as shown in the earlier application. As shown the Chamber 31a; is of larger diameter than either of the passages 30 or 33, but does not have to be of the exact size shown. The. borizontal portion 33 of the fuel conduit is of different diameters, that part of the passage lying between the chamber 3m and the point of connection with the main nozzle. being smaller than that part 331 of the passage 33 which lies to the left of the main nozzle in Fig. l. A plug 31 closes the left end of the passag-'e and a tube 33 is fitted in that. part of the fuel passage numbered 38. Such tube has a. restricted opening` 38a at its right end and terminates somewhat: to. the right of the Vertical passage 34. A plurality of orifi'ces 33 are provided immediately above the main. nozzle I! to admit air for purposes of effecting atomization of the fuel and a bushing 40 having a small orifice M therein is positioned within the main nozzle t2' to cause a now therethrough at high Velocity and to aid inthe atomization of the fuel. This fuel passage as so far described, is of the same construction as that shown in the earlier application, except that the chamber` 3ta is not disclosed therein. In such application a, passage .such as 3|) merely connects with another passage such as 33 of the same size as the passage 30,? the axis of which is. normal to thepassagc 3.0.

, In the earlier application the passages corresponding to 30 and: 33 were simple cylindrcal bores and formed a sharp corner' at the point where they connected. It was found that there ,was some tendency, particularly at high temperatures, for Vapor bubbles to form and collect in this corner and for such vapor bubbles to gradually grow in size until a bubble of such large size was formed that the flow of fuel through the passage was partly or wholly restricted, particularly during idling. This bubble would increase in size until the passage was nearly blocked and would then break loose and pass through the passage 33 and finally out into' the carburetor. This results in a somewhat intermittent and irregular flow of fuel, causihg some degree of irregularity of operation during idling. The device which constitutes the invention to which this application is directed is designed primarily to prevent any blocking of the fuel supply passage and any' irregularity of enginev operation resulting therefrom at any operating temperature. Therefore, instead of having a simple fuel conduit such as shown in` the earlier application and described above, according to the present invention, the chamber 3|a is provided at the point of connection of the passages 33 and 33. Asv already stated,

the walls of this chamber are tapered or flared, so as to present no sharp corner in which vapor bubbles would tend to collect and. build up as previouslydescribed, and while small bubbles are formed when Operating at relatively high temperatures1 these are not large enough to obstruct the fiow and simplyl movev along through the conduit. with the liquid fuel to the fuel inlets and into the mixture passage,

Asillnstrated the Chamber 31a has an upper surface which. inclined upwardly in the direction of fuel flow,A as indicated in Figs. l and 3, and has side walls: 43 and 41 which are flared outwardly in a. downward direction from the top surface 45 and terminate in the cylindrical opening 4d in which the upper end of the member 3| is received. The: Shape of the surfaces 46, 'llv and 48 will be readly' understood from Figs. 2, 5 and 6. As best shown in Fig. 2,. the surfaces 46 and 41 are also flared outwardly in thedirection of fuel fiow along the aXis. of the horizontal passage 33. Obv'iously, the top and sdes of the chamber 31a merge` into a single smooth surface free from any sharpi corners and pi'ogressively enlargi-ng in the direction of fuelv flow.`

This construction has been found to greatly reduce the tendency for bubbles to collect and form as previously described and,` in additionl there is provided a metal plate 49 which is secured in position by a press fit, or in` any other suitable way,, along the axis of the horizontal fuel passage 33, so as to separate such passage into anupper part 50 anda lower part 5|. It has been found that. such partition plate is more effective if itv is a little. shorter than that part. of the horizontal passage 33 between the chamber Bla. and the point of connection of passage 33 with the main nozzle. For example the partition may termnate somewhatto the right of the main fuel nozzle I2 'and somewhat to the left of the chamber 31a. Its length may vary to some extent, but excellent results are obtained if the plate is about four-fifths the length of -passage 33 between passage 30 and fuel inlet [2. or a little longer.

The above described partition plate performs 'several functions. First, it causes a flow through the upper part 50 of passage 33 at higher Velocity than the rate of flow in the lower part 5| of such passage. Second, it causes such small vapor bubbles as may be formed in the fuel passage to fiow principally through the space 50 above the plate, there being substantially no flow of bubbles through the space 5| below the plate, except at very high temperatures,` at which temperatures some hub'bl'es flow through this space, but such bubbles are not large enough to interrupt or retard flow of fuel in any way. Moreover, although the shape of chamber 31a is such as to substantially eliminate the formation of bubbles of' sufliciently large size to materially interfere with the flow of fuel, if a lbubble of such size does occasionally form .at high temperatures, the plate apparently breaks up such bubble so that even at high temperatures only bubbles of very small size pass through the passage 33 and such 'bubbles move at high Velocity and follow each other through the passage at more or less regular intervals so that there is no intermittent blocking of the passage either partially or wholly, and substantially no irregularty in fiow of fuel.

While the` embodiment of the present invention as herein disclosed, constitutes a preferredf form,

it is to be understood that other forms might be adopted.

What is claimed is as follows:

1. A carburetor for an internal combustion engine having, in combination, a Constant level fuelsupply Chamber, an intake passage provided with a throttle valve foi` controlling the flow of combustible mixture therethrough, air and fuel inlets for admitting air and fuel to said mixture passage, a fuel conduit for conveying fuel from said Constant level fuel chamber to the mixture passage, said fuel conduit comprising a first fuel passage which communicates directly with the fuel supply Chamber and a second passage comprising a substantially straight bore connecting the first passage with vthe fuel inlet, the wall surface of the said passages being so tapered at the point of connection thereof that the formation of any sharp corner at said point of connection is eliminated, whereby formation of vapor bubbles of sufcient size to cause apprecia'ble irregularity of fuel fiow is prevented at the point of connection of said passages.

2. A carburetor for an internal combustion engine having, in combination, a constant level fuel supply Chamber, an intake passage provided with a throttle valve for controlling the fiow of combustible mixture therethrough, air and fuel inlets for admitting air and fuel to said mixture passage, a fuel conduit for conveying fuel from said constant level fuel Chamber to the mixture passage, said fuel conduit comprising a passage which communicates with the fuel supply chamber and a second passage connecting directly with the fir'st passage and extending in a direction substantially normal to the axis of the first passage, the wall 'surface of the said passages being so tapered at the point of connection thereof that the formation of any sharp Corner at said point of connection is eliminated, whereby formation of vapor bubbles of sufiicient size to cause appreciable irregularity of fuel flow is prevented -at the point of connection of said passages and a partition in said second mentioned 'passage between its point of connection with the first mentioned passage and the fuel inlet, dividing said passage into two parts.

' 3. A carburetor for an internal combustion engine having, in combination, a constant level fuel supply Chamber, an intake passage provided with a throttle valve for controlling the fiow of' combustible mixture therethrough, air and fuel inlets for admitting air and fuel to said mixture passage, a fuel conduit for conveying fuel from said Constant level fuel Chamber to the mixture passage, said fuel conduit comprising a passage which communicates Wiht the fuel supply chamber and a second passage connecting directly with the 'first passage and extending in a direction substantially normal to the axis of the first pas- Sage, the wall surface of the said passages being so tapered at the point of connection thereof that the formation of any sharp corner at said point of connection is eliminated, whereby formation of vapor bubbles of sufficient size to cause appi'eciable irregularity of fuel fiow is prevented at the point of connection of said passages and a partition in said second mentioned passage between its point of connection With the first mentioned passage and the fuel inlet, said partition lying in a horizontal plane along the axis of said passage.

4. A carburetor for an internal combustionlevel fuel supply chamber, an intake passage provided with a throttle valve for Controlling the flow of combustible mixture therethrough, air and fuel inlets for admitting air and fuel to said mixture passage, a fuel conduit for Conveying fuel from said Constant level fuel Chamber to the mixture passage, said fuel conduit compris- 'mg a passage which communicates With the fuel supply Chamber and a second passage connecting directly with the first passage and extending in a direction substantially normal to the axis of the first passage, the wall surface of the said passages being so tapered at the point of connection thereof that the formation of any sharp Corner at said point of connection is eliminated, whereby formation of vapor bubbles of sufiicient size to cause appreciable irregularity of fuel flow is prevented at the point of connection of said passages and a partition in said second mentioned passage between its point of Connection with the first mentioned passage and the fuel inlet, the length of said partition being somewhat less than the length of said second mentioned passage between its point of Connection with the first mentioned passage and the fuel inlet.

5. A carburetor for an internal oombustion .engine having, in combination, a constant level fuel supply chamber, an intake passage provided with a throttle valve for controlling the fiow of combustible mixture therethrough, air and fuel inlets for admitting air and fuel to said mixture passage, a fuel conduit for conveying fuel from said Constant level fuel Chamber to tion engine having, in combination, a constant the mixture passage, said fuel conduit comprising a passage which communicates with the fuel supply cham'ber and a second passage connecting directly with the first passage and extending in a direction substantially normal to the aXis of the first passage, the wall surface of the said passages being so tapered at the point of connection thereof that the formation of any sharp corner at said point of connection is eliminated, whereby formation of vapor bubbles of suiiicient size to cause appreciable irregularity of 'fuel flow is prevented at the point of connection of said passages and a partition in said second mentioned passage between its point of connection with the first mentioned passage and the fuel inlet, the length of said partition being approxiinately four-fifths of the length of said passage from its point of connection With the first mentioned passage and the fuel inlet.

6. A carburetor for an internal Combustion engine having, in combination, a constant level fuel supply chamber, an intake passage provided with a throttle valve for controlling the fiow of combustible mixture therethrough, air and fuel inlets for admitting air and fuel to said mixture passage, a fuel conduit for conveying fuel from said constant level fuel Chamber to the mixture passage, said fuel conduit comprising a passage which communicates with the fuel supply chamber and a second passage connecting directly with the first passage and extending in a direction substantially normal to the axis of the first passage, the wall surface of the said passages being so tapered, at the point of connection thereof that the formation of any sharp corner at said point of connection is eliminated, whereby formation of vapor bubbles of sufiicient size to cause appreciable irregularity of fuel flow is prevented at the point of connection of said passages and a partition in said second mentioned passage between its point of connection with the first 'mentioned passage :and the fuel inlet, the length 'of said partiton being approximately four-iifths of the length of said passage `from its point of ,connection with the first mentioned passage and the ,fuel inlet and said partition being so positoned that it is spaced from the point of connection of the fuel passages and from the fuel inlet.

'7. A carburetor for .an internal combustion engine having, :in combination, a constant level fuel supply chamber, an intake vpassage provided with ,a throttle valve for controlling the flow of combustible mixture therethrough, air and fuel inlets for admitting air and fuel to said mixture passage, a fuel conduit for ,conveying fuel fron'l'v said constant level :fuel chamber to the mixture passage, :and comprising an 'upwardly eitending passage which communicates at its :lower end with the fuel chamber, a second passage comprising a ,substantially :straight bore and connecting the fuel inlet 'with 'the upper end of said first passage, 'the wall surface .of said passages being so tapered at the point `of ,connection thereof as to .eliminate the :formation of any sharp .corner ``and prevent the formation of vapor bubbles .of sufticient size to .cause irregularity 'in fuel flow and ,a partition in the horizontal passage dividing said `passage into upper and lower parts.

:8. A Vcarburetor for an internal combustion engine having, in combination, a constant level fuel supply chamber, an intake passage provided with `a throttle hvalve for ,controlling the flow of combustible mixture 'therethrough :air 'and fuel inlets for admitting air and fuel to said mixture passage, a fuel conduit for conveying fuel :from said constant level fuel chamber to the mixture passage, and comprising an upwardly extending passage which communicates at .its lower end with the fuel chamber, a second passage exw tending .substantially horizontally and connecting with the first passage, the wall surface of said passages being so tapered .at the point of connection thereof as to eliminate the formation of any sharp corner and prevent the formation of 'vapor bubbles of sufiicient size to .cause irregularity in fuel flow `and a partition in the horizontal passage dividing said passage into upper :and lower parts, the length of the partition in said horizontal passage being somewhat less than the length .of said .passage :from `its point ,of connection with the upwardly extending passage to the `.fuel inlet.

9. A .carburetor for an internal combustion engine having, in combination, a constant level fuel supply chamber, an intake passage provided with a throttle valve for controlling the flow of combustible mixture therethrough, air and fuel inlets for admitting air and fuel to said mixture passage, a fuel conduit for conveying fuel from said constant level fuel chamber to the mixture passage, and comprsing an upwardly extending passage which communicates at its lower end with the fuel chamber, a second passage extending substantially horizontally and connecting with the first passage, the wall surface of said passages being so tapered at the point of connection thereof as to eliminate the formation of any sharp corner and prevent the formation of vapor bubbles of sufiicient size to cause irregularity in fuel flow and a partition in the horizontal passage dividing said passage into upper and lower parts, the length of the partition in said horizontal passage being approximately four-fifths the length of the horizontal passage from its 'point of connection with the 'vertically extending passage, to the fuel inlet.

,10. A carburetor for an internal co'mbustion engine having, in combination, a constant level fuel supply chamber, an `intake passage provided with a throttle valve for controlling the flow of combustible mixture therethrough, air and fuel inlets for admitting air and fuel to said mixture passage, a fuel conduit for conveying fuel vfrom said `constant level fuel chamber to the mixture passage and comprising an upwardly extending passage which communicates at its lower end with the fuel chamber, a second Vpassage comprising a substantially straight bore connecting the upwardly extending passage and fuel inlet and forming a chamber at its point of connection with the upwardly extending passage, the side walls `of said chamber being fiared outwardly in a downward direction and also horizontally in the direction of :flow of fuel therethrough in order 'to facilitate the flow of ,fuel therethrough and prevent the ;retention 'theren of vapor bubbles of sufiicient size to interfere with the flow of fuel.

1`1. ,A carburetor for :an :internal oombustion engine having, in combination, a constant level fuel supply chamber, an 'intake .passage provided with a throttle valve for controlling the V:flow ;of combustible mixture therethrough, air .and fuel inlets for admitting air and ;fuel to `said mixture passage, a fuel ,conduit for Lconveying fuel from said constant level fuel chamber to the mixture passage, and comprisi-ng .an upwardly extending passage which communicates .at its .lower end with the fuel chamber, a second passage .comprising a substantially straight bore connecting the upwardly extending zpassages and fuel inlet andforming a chamberat its point of connection with the upwardly extending passage `having side walls 'which are fiared outwardly in a downward direction and horizontally in the -direction of flow of fuel therethrough, and a top surface tapered upwardly in the direction `of flow of fuel therethrough, whereby the flow of fuel is faci'litated and the retention `of vapor 'bubbles therein of sufiicient size to interfere with the fuel flow is prevented.

12. Yoarbureter for ;an internal combostion engine having, in combination, a constant level fuel ,supply chamber, an intake passag-e provided with a throttle valve .for controlling the flow 'of coinioustible mixture therethrough, air and fuel inlets tor Vadm'i'tting air ,and .fuel to said mixtu-re passage, fuel cond'uit tor conveyng tue'l from said Constant level fuel chamber to the mixture passage, and comprising an upwardly extending passage which communicates at its lower end with the fuel chamber, a second passage comprising a substantially straight bore connecting the upwardly extending passages and fuel inlet and forming a chamber at its point of connection with the upwardly extending passage, of larger cross sectional area than either of Said passa-gas and havin'7 tapered side and top Walls so that said chamber has no sharp Corners formed therein and the formation therein of vapor bubbles of sufficient size to cause apprecia-ble irregularity in flow of fuel therethrough is prcvented.

13. A carburetor for an internal combustion engine having, in combination, a Constant level fuel supply chamber, an intake passage provided with a throttle valve for controlling the flow of 'combnstible mixture therethrough, air and fuel inlets for admitting air and fuel to said auxiliary passage, a fuel Condut for Conveying fuel from said Constant level fuel Chamber to the mixture passage and Comprising a generally Vertical passage formed in al member extending down- Wardly into the fuel in said fuel Chamber and entirely surrounded by the fuel therein in order to prevent the heating of said member by Conductivity and to reduce the formation of vapor bubbles in said passage, a second passage comprising a substantially straight bore Connecting the lvertiCal passa-ge at its upper end and forming a Chamber at its point of Connection With the Vertical passage having tapered side and top Walls, Whereby the retention in said Chamber of any vapor bubbles that may be formed is prevented and the fiow of fuel therethrough is faoilitated.

14. A carburetor for an internal Combustion engine having, in combination, a Constant level fuel supply Chamber, an intake passagefprovided With a throttle Valve for Controlling the fiow of Combustible mixture therethrough, air and fuel inlets for admitting air and fuel to said mixture passage, a fuel Conduit for Conveying fuel from said Constant level fuel Chamber to the mixture passage and Comprising a generally vertical passage formed in a member extending downwardly into the fuel in said fuel Chamber and entirely surrounded by the fuel therein in order to prevent the heating of said member by Conductivity and to reduce the formation of vapor bubbles in said passage, a substantially horizontal passage Connecting directly With the Vertical passage at its upper end so as to form a Chamber at its point of connection With the Vertical passage having tapered side and top Walls, Whereby the retention in said Chamber of any vapor bubbles that may be formed is prevented and the flow of fuel therethrough is facilitated and a partition in the h-orizontal passage dividing such passage into two parts.

15. A lCarburetor for an internal Combustion engine having, in combination, a Constant level fuel supply Chamber, an intake passage provided With a throttle valve for controlling the flow of Combustible mixture therethrough, air and fuel inlets for admitting air and fuel to said mixture passage, a fuel Conduit for Conveying fuel from said Constant level fuel Chamber to the mixture passage and Comprising a generally Vertical passage formed in a member extending downwardly into the fuel in said fuel Chamber and entirely surrounded by the fuel therein in order to prevent the heating of said member by Conductivity and to reduce the formation of vapor bubbles in said passage, a substantially' horizontal passage connecting With the Vertical passage at its upper end so as to form a chamber at its point of connection with the Vertical passage having tapered side and top Walls, whereby the retention in said Chamber of any vapor bubbles that may be formed is prevented and the flow of fuel therethrough is facilitated and a partition in the horizontal passage dividing such passage into two parts, said partition being of a length somewhat less than the length of said horizontal passage from said Chamber to the fuel nozzle.

16. A Carburetor for an internal combustion engine having, in Combination, a Constant level fuel supply Chamber, an intake passage pro-- vided with a throttle valve for Controlling the fiow of Combustib'le mixture therethrough, air and fuel inlets for a'dmitting air and fuel to said mixture passage, a fuel Conduit for conveying fuel from said Constant level fuel Chamber to the mixture vpassa-ge and Comprising a generally Vertical passage formed in a member extending downwardly into the fuel in said fuel Chamber and entirely surrounded by the fuel therein in order to prevent the heating of said member by conductivity and to reduce the formation of vapor bubbles in said passage, a substantially horizontal passage oonnecting with the Vertical passage at its upper end so 'as to forma Chamber at its point of Connection With the Vertical passage having tapered side and top walls, whereby the retention in said Chamber of any vapor bubbles that may be formed is prevented andv the fiow of fuel therethrough is facilitated and a partition in the horizontal passage, 'said partition lying on a horizontal plane and dividing said passage into upper .and lower parts.

ELMER oLsoN.

References Cited in the file of this patent UNITED STATES PATENTS 'Carlson Mar. 25, 1947 

